给定一个链表。任务是从链接列表的末尾删除第N个节点。
例子：
Input : 1->2->3->4->5 , N = 2
Output : 1->2->3->5
Input : 7->8->4->3->2 , N = 1
Output : 7->8->4->3
先决条件：
1.从链接列表中删除一个节点。
2.从链接列表的末尾找到第n个节点
方法：
从最后删除第B个节点与从开始删除(length-B + 1)基本相同。在我们的方法中，我们首先评估链表的长度，然后检查
- 如果长度
- 如果length = B，则返回head-> next
- 如果长度> B，则意味着我们必须删除中间节点，我们将删除此节点，并使它的上一个节点指向已删除节点的下一个节点。
C++
// CPP program to delete nth node from last
#include
using namespace std;
// Structure of node
struct Node {
int data;
struct Node* next;
};
// Function to insert node in a linked list
struct Node* create(struct Node* head, int x)
{
struct Node *temp, *ptr = head;
temp = new Node();
temp->data = x;
temp->next = NULL;
if (head == NULL)
head = temp;
else {
while (ptr->next != NULL) {
ptr = ptr->next;
}
ptr->next = temp;
}
return head;
}
// Function to remove nth node from last
Node* removeNthFromEnd(Node* head, int B)
{
// To store length of the linked list
int len = 0;
Node* tmp = head;
while (tmp != NULL) {
len++;
tmp = tmp->next;
}
// B > length, then we can't remove node
if (B > len)
{
cout << "Length of the linked list is " << len;
cout << " we can't remove "<< B << "th node from the";
cout << " linked list\n";
return head;
}
// We need to remove head node
else if (B == len) {
// Return head->next
return head->next;
}
else
{
// Remove len - B th node from starting
int diff = len - B;
Node* prev= NULL;
Node* curr = head;
for(int i = 0;i < diff;i++){
prev = curr;
curr = curr->next;
}
prev->next = curr->next;
return head;
}
}
// This function prints contents of linked
// list starting from the given node
void dispaly(struct Node* head)
{
struct Node* temp = head;
while (temp != NULL) {
cout << temp->data << " ";
temp = temp->next;
}
cout << endl;
}
// Driver code
int main()
{
struct Node* head = NULL;
head = create(head, 1);
head = create(head, 2);
head = create(head, 3);
head = create(head, 4);
head = create(head, 5);
int n = 2;
cout << "Linked list before modification: \n";
dispaly(head);
head = removeNthFromEnd(head, 2);
cout << "Linked list after modification: \n";
dispaly(head);
return 0;
} Java
// Java program to delete nth node from last
class GFG
{
// Structure of node
static class Node
{
int data;
Node next;
};
// Function to insert node in a linked list
static Node create(Node head, int x)
{
Node temp, ptr = head;
temp = new Node();
temp.data = x;
temp.next = null;
if (head == null)
head = temp;
else
{
while (ptr.next != null)
{
ptr = ptr.next;
}
ptr.next = temp;
}
return head;
}
// Function to remove nth node from last
static Node removeNthFromEnd(Node head, int B)
{
// To store length of the linked list
int len = 0;
Node tmp = head;
while (tmp != null)
{
len++;
tmp = tmp.next;
}
// B > length, then we can't remove node
if (B > len)
{
System.out.print("Length of the linked list is " + len);
System.out.print(" we can't remove "+ B +
"th node from the");
System.out.print(" linked list\n");
return head;
}
// We need to remove head node
else if (B == len)
{
// Return head.next
return head.next;
}
else
{
// Remove len - B th node from starting
int diff = len - B;
Node prev= null;
Node curr = head;
for(int i = 0; i < diff; i++)
{
prev = curr;
curr = curr.next;
}
prev.next = curr.next;
return head;
}
}
// This function prints contents of linked
// list starting from the given node
static void dispaly(Node head)
{
Node temp = head;
while (temp != null)
{
System.out.print(temp.data + " ");
temp = temp.next;
}
System.out.println();
}
// Driver code
public static void main(String[] args)
{
Node head = null;
head = create(head, 1);
head = create(head, 2);
head = create(head, 3);
head = create(head, 4);
head = create(head, 5);
int n = 2;
System.out.print("Linked list before modification: \n");
dispaly(head);
head = removeNthFromEnd(head, 2);
System.out.print("Linked list after modification: \n");
dispaly(head);
}
}
// This code is contributed by Rajput-JiPython3
# Python3 program to delete nth node from last
class Node:
# Function to initialise the node object
def __init__(self, data):
self.data = data # Assign data
self.next = None # Initialize next as null
class LinkedList:
# Function to initialize head
def __init__(self):
self.head = None
# Function to add node at the end
def create(self, x):
new_node = Node(x)
if self.head is None:
self.head = new_node
return
last = self.head
while last.next:
last = last.next
last.next = new_node
# This function prints contents of linked
# list starting from the given node
def display(self):
temp = self.head
while temp:
print(temp.data, end = " ")
temp = temp.next
# Function to remove nth node from last
def removeNthFromEnd(head, k):
# the function uses two pointer method
first = head
second = head
count = 1
while count <= k:
second = second.next
count += 1
if second is None:
head.value = head.next.value
head.next = head.next.next
return
while second.next is not None:
first = first.next
second = second.next
first.next = first.next.next
# Driver code
# val list contains list of values
val = [1, 2, 3, 4, 5]
k = 2
ll = LinkedList()
for i in val:
ll.create(i)
print("Linked list before modification:");
ll.display()
removeNthFromEnd(ll.head, k)
print("\nLinked list after modification:");
ll.display()
# This code is contributed by DhineshC#
// C# program to delete nth node from last
using System;
class GFG
{
// Structure of node
class Node
{
public int data;
public Node next;
};
// Function to insert node in a linked list
static Node create(Node head, int x)
{
Node temp, ptr = head;
temp = new Node();
temp.data = x;
temp.next = null;
if (head == null)
head = temp;
else
{
while (ptr.next != null)
{
ptr = ptr.next;
}
ptr.next = temp;
}
return head;
}
// Function to remove nth node from last
static Node removeNthFromEnd(Node head, int B)
{
// To store length of the linked list
int len = 0;
Node tmp = head;
while (tmp != null)
{
len++;
tmp = tmp.next;
}
// B > length, then we can't remove node
if (B > len)
{
Console.Write("Length of the linked list is " + len);
Console.Write(" we can't remove " + B +
"th node from the");
Console.Write(" linked list\n");
return head;
}
// We need to remove head node
else if (B == len)
{
// Return head.next
return head.next;
}
else
{
// Remove len - B th node from starting
int diff = len - B;
Node prev= null;
Node curr = head;
for(int i = 0; i < diff; i++)
{
prev = curr;
curr = curr.next;
}
prev.next = curr.next;
return head;
}
}
// This function prints contents of linked
// list starting from the given node
static void dispaly(Node head)
{
Node temp = head;
while (temp != null)
{
Console.Write(temp.data + " ");
temp = temp.next;
}
Console.Write("\n");
}
// Driver code
public static void Main(String[] args)
{
Node head = null;
head = create(head, 1);
head = create(head, 2);
head = create(head, 3);
head = create(head, 4);
head = create(head, 5);
Console.Write("Linked list before modification: \n");
dispaly(head);
head = removeNthFromEnd(head, 2);
Console.Write("Linked list after modification: \n");
dispaly(head);
}
}
// This code is contributed by 29AjayKumar输出：
Linked list before modification:
1 2 3 4 5
Linked list after modification:
1 2 3 5